Molecular characterization of antimicrobial multi-drug resistance in non-typhoidal Salmonellae from chicken and clam in Mangalore, India

Salmonella enterica has been documented as one of the leading causes of salmonellosis throughout the world and is most commonly associated with the consumption of contaminated food products. Thus, this research was aimed at studying the antimicrobial susceptibility pattern and detection of quinolone resistance in Salmonella spp isolated from food of animal origin. Thirty-six Salmonella isolates comprising 8 from poultry and 28 from seafood（clams） were identified, serotyped and characterized for their antimicrobial susceptibility against 10 different antibiotics. Plasmid DNA was isolated from all the isolates by alkaline lysis, quinolone resistant non-typhoidal S. Weltevreden were examined for mutation in the DNA gyrase coding gene. Among the 36 Salmonella isolates, 20 were S. weltevreden（8 from poultry and 12 from seafood） and 16 were S. Typhimurium（from seafood）. All the isolates showed multiple resistance to nalidixic acid, tetracycline, co-trimoxazole and nitrofurantoin, but, interestingly, the isolates were 100% susceptible to ampicillin, chloramphenicol and gentamicin. Resistant isolates from the study carried the genes responsible for resistance to respective antibiotics. The strain S130 isolated in the study showed single point mutation,Asp87Gly, at position 87 in quinolone resistance determining region. It revealed mutation in quinolone resistance determining region as a cause for quinolone resistance in non-typhoidal Salmonellae. The occurrence of genes accountable for plasmid mediated resistance to quinolones（viz., qnrA, qnrB and qnrS） in plasmid of non-typhoidal Salmonellae isolates provides evidence for plasmid mediated quinolone resistance.

Comparison of the Detection Results of Salmonellae in Samples by Two Methods

Salmonellae samples provided by FAPAS were detected by VIDAS and GB 4789.4-2016,respectively.The advantages and disadvantages of each detection method were discussed in the paper,so as to provide theoretical support for the detection of Salmonellae.

Occurrence of Typhoidal and Non-Typhoidal Salmonellae among Poultry Workers in the Southern, Nigeria

Typhoid fever and non-typhoidal salmonellosis remain endemic in most developing countries with large scale transmission through contaminated food and drinking water. Since the early 2000s, poultry has also been found to be a common food source for Salmonella enteritidis infections. A total of 500 blood, stool, cloaca swab and egg shell swab specimens were collected respectively from poultry, non-poultry workers and birds in Akwa Ibom State and screened for Salmonella species using standard cultural and serological techniques. The overall prevalence rate was 117 (23.4%). Salmonella species were distributed in all the three senatorial districts of the State, percentage distribution of Salmonella isolates was 42 (25%) for Uyo, 35 (20.8%) for Eket and 40 (23.8%) were isolated from Ikot Ekpene senatorial districts. Out of 372 human subjects screened 77 (20.7%) were positive and 38 (20.4%) were isolated from non-poultry workers while 39 (21.0%) were isolated from poultry Staff in the three senatorial districts. Out of 128 samples of poultry products analysed 40 (31.3%) were isolated. 23 (18%) were isolated from cloaca swabs while 17 (13.3%) were isolated from egg shell swabs. In this study, all the serological significant Typhoid fever cases were confirmed by blood culture. According to sero-grouping and source of sample collection 23.9% S. typhi was isolated from human followed by S. paratyphi A (20.5%) while S. enteritidis and S. gallinarum (19.7%). Among poultry products S. gallinarum, S. enteritidis, S, pullorum, S. paratyphi A, and S. typhimurium were isolated from bird Cloaca swab and Egg shell swab. Salmonella pullorum and S. typhi were not isolated from human and poultry respectively. High prevalence of Salmonella serovars such as S. gallinarium, S. typhi, S. Typhimurium and S. enteritidis with regular consumption of poultry and eggs without proper disinfection and appropriate boiling represent a serious public health risk in Akwa Ibom State. Demographic data obtained in this study showed that majority of the poultry workers across the three senatorial districts were within the ages of 21 to 30 (34%), 39% were none graduate while 30.4% were secondary school leavers. Fever was recorded as the highest clinical signs and symptoms followed by headache, abdominal cramps, diarrhoea and vomiting. Generally, all the isolates identified as Salmonella were tested for their susceptibility to antimicrobial agents. The results showed that Amoxacillin-Clavulanic acid was 100% susceptible to S. gallinarum, S. paratyphi A, 93% susceptible to S. typhi and 80% to S. typhimurium, S. enteritidis and S pullorum. Salmonella gallinarum was 100% sensitive to Ciprofloxacin and S. pullorum, whereas all isolates were 100% resistant to Oxacillin and Tylosin antibacterial agents used. The emergence of multiple drugs resistant Salmonella from human and poultry shows that the continuous use of drugs in poultry as growth promoters should be re-examined. Other factors as sources of Salmonella contamination in farms can be minimized by good hygienic practices and biosecurity measures.

从H1N1血凝素序列提取的沙门氏菌传递的COBRA-HA1抗原对甲型流感亚型产生广谱保护作用

A universal vaccine is in high demand to address the uncertainties of antigenic drift and the reduced effectiveness of current influenza vaccines.In this study,a strategy called computationally optimized broadly reactive antigen(COBRA)was used to generate a consensus sequence of the hemagglutinin globular head portion(HA1)of influenza virus samples collected from 1918 to 2021 to trace evolutionary changes and incorporate them into the designed constructs.Constructs carrying different HA1regions were delivered into eukaryotic cells by Salmonella-mediated bactofection using a Semliki Forest virus RNA-dependent RNApolymerase(RdRp)-based eukaryotic expression system,pJHL204.Recombinant protein expression was confirmed by Western blot and immunofluorescence assays.Mice immunized with the designed constructs produced a humoral response,with a significant increase in immunoglobulin G(IgG)levels,and a cell-mediated immune response,including a 1.5-fold increase in CD4^(+) and CD8^(+)T cells.Specifically,constructs #1 and #5 increased the production of interferon-γ(IFN-γ)producing CD4^(+)and CD8^(+)T cells,skewing the response toward the T helper type 1 cell(Th1)pathway.Additionally,interleukin-4(IL-4)-producing T cells were upregulated 4-fold.Protective efficacy was demonstrated,with up to 4-fold higher production of neutralizing antibodies and a hemagglutination inhibition titer>40 against the selected viral strains.The designed constructs conferred a broadly protective immune response,resulting in a notable reduction in viral titer and minimal inflammation in the lungs of mice challenged with the influenza A/PR8/34,A/Brisbane/59/2007,A/California/07/2009,KBPV VR-92,and NCCP 43021 strains.This discovery revolutionizes influenza vaccine design and delivery;Salmonella-mediated COBRA-HA1 is a highly effective in vivo antigen presentation strategy.This approach can effectively combat seasonal H1N1 influenza strains and potential pandemic outbreaks.

Anti-biofilm and anti-virulence potential of cell free supernatant of Akkermansia muciniphila against Salmonella

Akkermansia muciniphila is one of the commensals residing within the mammalian gut and co-evolving with the host.Numerous studies have demonstrated the benefits of A.muciniphila in ameliorating metabolic disorders,while little is known about the antimicrobial potential of A.muciniphila against pathogens.Here,we examined the antimicrobial and anti-virulence properties of cell free supernatant(CFS)of A.muciniphila against Salmonella Typhimurium.CFS retarded bacterial growth and inhibited the motility of S.Typhimurium SL1344 and S.Typhimurium 14028.CFS dose-dependently reduced cell hydrophobicity and auto-aggregation of both strains.Also,CFS from A.muciniphila significantly attenuated biofilm formation.Compared with untreated bacteria,CFS-treated bacteria significantly decreased adhesion and invasion to Caco-2 cells,and reduced intracellular survival in macrophages.CFS maintained antimicrobial properties after treatment with high temperatures and various proteases,while it lost its antimicrobial activity after pH neutralization.Gas chromatography-mass spectrometry(GC-MS)confirmed that A.muciniphila produced a certain amount of acetate and propionate,and ultra-high-performance liquid chromatography-mass spectrometry(UHPLCMS)identified other organic acids and metabolites in CFS.In summary,CFS from A.muciniphila exhibited anti-biofilm and anti-virulence properties against Salmonella and could be potentially utilized in the food industry for controlling Salmonella contamination and reducing infection.

Typhoid fever presenting as neuropsychiatric oddities:A case report

Rationale:Salmonella is a common etiological agent behind the tropical fever syndrome in the Indian subcontinent.Its prevalence in India remains high due to a lack of proper sanitation services in large parts of the country.Its neuropsychiatric manifestations is rare and the understanding on their pathophysiology is still poor.Patient concerns:A 19-year-old male,presented with a 10-day history of altered mental status,high-grade fever and violent behaviour.2 Days prior to admission,he developed decreased responsiveness and a muttering delirium with self-talking.Diagnosis:Coma vigil secondary to salmonellosis.Interventions:Intravenous ceftriaxone and dexamethasone.Outcomes:The resolution of the coma vigil and the associated Salmonella infection were observed;however,the patient developed residual mutism.Lessons:The atypical presentation of a globally obtunded state followed by mutism in typhoid coma in this case should be brought to the attention of clinicians worldwide.Additionally,the enduring speech limitations and potential psychiatric consequences may be linked to the prolonged duration of the infection.

Low interleukin-10 level indicates a good prognosis in Salmonella enterica serovar typhimurium-induced pediatric hemophagocytic lymphohistiocytosis:A case report

BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.

Antibiotic Resistance Profile of Salmonella Strains Isolated at the National Clinical Biology and Public Health Laboratory in Bangui, Central African Republic

In Africa, each year, there are estimated to be more than 91 million cases of salmonellosis and 137,000 cases of death. The problem of antibiotic resistance in Salmonella strains is a threat to public health. The objective of this study is to evaluate the antibiotic resistance profile of Salmonella strains isolated in biological products analyzed at the National Laboratory of Clinical Biology and Public Health (NLCBPH) in Bangui. This is, therefore, a cross-sectional study with a descriptive aim, running from January to December 2022. It focused on the strains of Salmonella isolated and identified in stools, urines, and blood samples. For each strain of Salmonella isolated, an antibiogram was carried out following the recommendations of the French Society of Microbiology (CASFM, 2022). A total of 93 strains of Salmonella have been recorded. The age group 0 - 9 years was 29% and that of >50 years was 11%. The median age of patients was 30 years with a minimum of 1 and a maximum of 78 years. The female gender was more represented at 52.69% than the male gender at 47.31%, i.e. a sex ratio of 0.89 (M/F). Salmonella strains were much more isolated in stools at 62% followed by urines at 29% and blood at 6%. Salmonella arizonae strains were more represented with 52%. Salmonella strains have a resistance rate to Tetracycline of 62.37% followed by Penicillins of 50%. The rate of multi-antibiotic resistance of the Salmonella strains isolated represented 48.38%. Salmonella spp. strains were multi-resistant at 58.69% followed by Salmonella arizonae strains at 47.91%. There is a significant association between the different families of antibiotics and Salmonella strains (p < 0.05). According to the results obtained, Penicillins, Phenicoles, and Cyclins had a high rate of resistance on Salmonella strains. No strain-producing Broad Spectrum Beta-lactamase has been isolated. Salmonella strains represent a zoonotic health danger, constitute a public health problem and remain a current subject. This germ is resistant to the antibiotics used. It is, therefore, essential to emphasize monitoring the resistance of these germs in the Central African Republic (CAR) to improve the health of the population.

Prevalence and Characterization of Pathogens Responsible for Enteric Fever and Assessment of Their Antibiotic Susceptibility Pattern in Bangladesh

In Bangladesh, Enteric fever is a persistent health issue throughout the year, occasionally reaching epidemic levels. The growing antibiotic resistance makes treatment increasingly challenging. Therefore, studying the antibiotic resistance patterns within the population is crucial to ensure a more effective treatment strategy. This study was designed to determine the prevalence, antimicrobial susceptibility profile, and factors associated with Salmonella spp. infections among clinically suspected Enteric fever patients in Bangladesh. This study also aimed to investigate whether there has been a re-emergence in the susceptibility of bacterial strains to conventional drugs. Data were collected from February 2024 to July 2024, from patients suspected Enteric fever (fever less than seven days duration) in a Private Diagnostic Center of Bangladesh. A total of 195 blood samples were cultured, where 53.85% came out positive, among which 79.05% Salmonella typhi and 20.95% Salmonella paratyphi A were found. Prevalence of Typhoid fever was observed high among the school-going age group (0 - 15 years) patients. Both these organisms were susceptible to ceftazidime, cefixime, ceftriaxone and cefepime but resistant to nalidixic acid, ciprofloxacin and levofloxacin. Nalidixic Acid is resistant to all S. paratyphi A and sensitive to few S. typhi. Ciprofloxacin and levofloxacin showed delayed response (36.14% and 22.72% sensitive to S. typhi and S. paratyphi A, respectively) and resistance (63.85% and 77.27% resistant to S. typhi and S. paratyphi A, respectively). In case of S. typhi, the resistance was found against ampicillin (32.53%), chloramphenicol (27.71%), cotrimoxazole (24.09%) and the resistance of S. paratyphi A found against ampicillin (4.54%), chloramphenicol (0%) and cotrimoxazole (0%). This study will provide clinicians with alternative drug options and facilitate the effective treatment of Enteric fever.

Case Report: Bilateral Intra-Parenchymal Hematomas Caused by Ventricular Flood Complicating Neonatal Salmonella typhi Meningitis

Salmonella meningitis is an uncommon condition in neonates, and when it does occur, it is often linked to serious complications, such as subdural collections and abscesses. We present a case involving a 23-day-old neonate diagnosed with Salmonella meningitis, who developed complications including bilateral intra-parenchymal hematomas with ventricular involvement. The infant showed significant improvement following an extended course of systemic antibiotics and supportive care.

Comparative Study of the Widal Test against Stool Culture in the Diagnosis of Suspected Cases of Typhoid Fever in Some Low Income Communities in the Adamawa Region of Cameroon

Introduction: Infectious diseases constitute a major concern of public health in developing countries. Facilities and well trained staff have been shown to be one of the major obstacles in the rapid and quality diagnosis of these diseases. As such, we carried out an analysis to compare the Widal test and stool culture to identify febrile patients with Salmonella infection. Method: A cross sectional study was conducted to diagnose salmonella infection with out-patients who demonstrated signs of salmonella infection. Serum was harvested from blood collected from 368 (Vina = 234, Mayo Banyo 65, and Djerem = 69) patients accompanied by stool, Widal test was conducted on the spot and stool was taken to a reference laboratory for culture using standard microbiological methods, sociological set up was calculated in percentages, prevalence was calculated using excel while statistical difference was calculated using SPSS. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to compare the Widal test against stool culture. Results: A total of 368 (50.8% females and 49.2% males) participants took part in the survey. Salmonella prevalence (66.24%) in stool culture in the Vina division was significantly different (p 0.05). The sensitivity,specificity, PPV, and NPV of slide agglutination test against stool culture varied from different areas (Vina: 51.6%, 73.62%, 79.21% and 43.61%;Mayo Banyo: 60.53%, 77.78%, 79.31% and 58.33%;Djerem: 53.18%, 83.73% 73.91% and 67.39%) respectively. Slide agglutination test has a fair agreement with the stool culture (kappa, Vina = 0.202;Mayo Banyo = 0.37 and Djerem = 0.38). Conclusion: Generally, in the three areas of study, the Widal test had a fair correlation with the stool culture;This means the Widal test should not be used alone but in combination with stool culture in the detection of salmonella infections.

Comparative antimicrobial activity in Murrah buffalo (Bubalus bubalis) Heifers’ urine and urine distillate

Background:Murrah buffalo is a breed of water buffalo(Bubalus bubalis)reared for milk and meat,especially in Northern India.There are so many studies on the antimicrobial potential of the cow(Bos indicus)urine but buffalo urine has rarely been studied.This study was aimed to evaluate the antimicrobial activity in whole buffalo urine and its distillate.Methods:Urine specimens were collected from seven Murrah buffalo heifers in the morning over three days from all seven heifers and distillated to prepare urine distillate(UD).The antimicrobial activity was determined through 96 well microplate method diluting(1:1)urine and UD in Mueller Hinton liquid medium against 919 microbial strains belonging to 148 species of 49 genera(Candia,11 genera of Gram+ve bacteria,37 genera of Gram-ve bacteria).The test strains were taken from the repository,revived and tested for purity before testing.The test strains were of clinical origin(372),environmental origin(496)and also from reference strain repositories(51).Results:Of the 919 test strains,a total of 57.89%and 56.04%of the tested strains were susceptible to UD and urine,respectively.There was a no significant(p>0.4)difference in the antimicrobial activity of UD and urine against 919 strains of microbes,regardless of their genus,species,and Gram staining reaction.Similarly,there was no significant(p>0.4)difference between the susceptibility of bacterial and Candida strains to UD or urine.However,strains of clinical origin were more often resistant to buffalo UD and urine(p<0.01)than strains isolated from environmental sources irrespective of their Gram staining characteristics(p>0.05).A significantly(p<0.01)higher proportion of reference strains was susceptible to UD and urine than microbial strains of clinical and environmental origin.For buffalo urine and UD,the most susceptible strains were Stenotrophomonas maltophilia(13/13)followed by Citrobacter freundii(8/10);Salmonella enterica ssp.enterica(21/27),Geobacillus stearothermophilus(23/30),Staphylococcus aureus(13/17),and Paenibacillus larvae(7/10)strains.The most resistant strains belonged to Acinetobacter calcoaceticus(15/20)species followed by strains of Paenibacillus alvei(11/16),Edwardsiella tarda(20/30),Bacillus megaterium(7/11)and Escherichia coli(59/110)species.There was insignificant(p,>0.05)difference in susceptibility of strains of different species of the same genus;however,among all the Bacillus species strains of B.coagulans were the most susceptible(66.7%)and strains of B.megaterium were the least susceptible(36.4%),similarly Enterococcus faecium strains were more susceptible(68.2%)than strains of Enterococcus faecalis(38.9%),70%strains of P.larvae were susceptible to urine and UD but only 31.3%of strains of P.alvei were susceptible.Strains of Klebsiella pneumoniae and Raoultella terrigena,earlier belonging to the same genus Klebsiella,had comparable susceptibility to buffalo urine and UD.Conclusion:The study concluded that buffalo urine may be a potential antimicrobial and may be explored further for identification of active antimicrobial compounds in buffalo urine.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Dietary supplemental coated essential oils and organic acids mixture improves growth performance and gut health along with reduces Salmonella load of broiler chickens infected with Salmonella Enteritidis

Background Reducing Salmonella infection in broiler chickens by using effective and safe alternatives to antibiotics is vital to provide safer poultry meat and minimize the emergence of drug-resistant Salmonella and the spread of salmonellosis to humans.This study was to first evaluate the protective efficacy of feeding coated essential oils and organic acids mixture(EOA)on broiler chickens infected with Salmonella Enteritidis(S.Enteritidis,SE),and then its action mechanism was further explored.Methods A total of 4801-day-old Arbor Acres male chickens were randomly assigned into five treatments with six replicates,including non-challenged control fed with basal diet(A),SE-challenged control(B),and SE-infected birds fed a basal diet with 300 mg/kg of EOA(BL),500 mg/kg of EOA(BM)and 800 mg/kg of EOA(BH),respectively.All birds on challenged groups were infected with Salmonella Enteritidis on d 13.Results Feeding EOA showed a reversed ability on negative effects caused by SE infection,as evidenced by decreasing the feed conversion rate(FCR)and the ratio of villus height to crypt depth(VH/CD)(P<0.05),obviously decreasing intestinal and internal organs Salmonella load along with increasing cecal butyric acid-producing bacteria abundance(P<0.05).Moreover,supplemental different levels of EOA notably up-regulated claudin-1(CLDN-1),occludin(OCLN),zonula occludens-1(ZO-1),mucin-2(MUC-2),fatty acid binding protein-2(FABP-2),nuclear factor kappa-light-chainenhancer of activated B cells(NF-κB),myeloid differential protein-88(MyD88)and interleukin-6(IL-6)mRNA levels in the ileum of the infected chickens after challenge,whereas down-regulated toll-like receptor-4(TLR-4)mRNA levels(P<0.05).Linear discriminant analysis combined effect size measurements analysis(LEfSe)showed that the relative abundance of g_Butyricicoccus,g_Anaerotruncus and g_unclassified_f_Bacillaceae significantly was enriched in infected birds given EOA.Also,phylogenetic investigation of communities by reconstruction of unobserved states(PICRUSt)analysis showed that alpha-linolenic acid metabolism,fatty acid metabolism and biosynthesis of unsaturated fatty acids were significantly enriched in the EOA group.Conclusion Our data suggest that the essential oils and organic acids mixture can be used as an effective strategy to ameliorate and alleviate Salmonella Enteritidis infection in broilers.

Dietary supplementation of bilberry anthocyanin on growth performance,intestinal mucosal barrier and cecal microbes of chickens challenged with Salmonella Typhimurium

Background Anthocyanins(AC)showed positive effects on improving the intestinal health and alleviating intestinal pathogen infections,therefore,an experiment was conducted to explore the protective effects of supplemented AC on Salmonella-infected chickens.Methods A total of 240 hatchling chickens were randomly allocated to 4 treatments,each with 6 replicates.Birds were fed a basal diet supplemented with 0(CON,and ST),100(ACL)and 400(ACH)mg/kg of AC for d 60,and orally challenged with PBS(CON)or 10^(9) CFU/bird(ST,ACL,ACH)Salmonella Typhimurium at d 14 and 16.Results(1)Compared with birds in ST,AC supplementation increased the body weight(BW)at d 18 and the average daily gain(ADG)from d 1 to 18 of the Salmonella-infected chickens(P<0.05);(2)AC decreased the number of Salmonella cells in the liver and spleen,the contents of NO in plasma and inflammatory cytokines in ileal mucosa of Salmonella-infected chickens(P<0.05);(3)Salmonella infection decreased the ileal villi height,villi height to crypt depth(V/C),and the expression of zonulaoccludins-1(ZO-1),claudin-1,occludin,and mucin 2(MUC2)in ileal mucosa.AC supplementation relieved these adverse effects,and decreased ileal crypt depth(P<0.05);(4)In cecal microbiota of Salmonella-infected chickens,AC increased(P<0.05)the alpha-diversity(Chao1,Pd,Shannon and Sobs indexes)and the relative abundance of Firmicutes,and decreased(P<0.05)the relative abundance of Proteobacteria and Bacteroidota and the enrichment of drug antimicrobial resistance,infectious bacterial disease,and immune disease pathways.Conclusions Dietary AC protected chicken against Salmonella infection via inhibiting the Salmonella colonization in liver and spleen,suppressing secretion of inflammatory cytokines,up-regulating the expression of ileal barrier-related genes,and ameliorating the composition and function of cecal microbes.Under conditions here used,100 mg/kg bilberry anthocyanin was recommended.

Pretreatment with probiotics Enterococcus faecium NCIMB 11181 attenuated Salmonella Typhimurium-induced gut injury through modulating intestinal microbiome and immune responses with barrier function in broiler chickens

Background:Preventing Salmonella infection and colonization in young birds is key to improving poultry gut health and reducing Salmonella contamination of poultry products and decreasing salmonellosis for human consumption(poultry meat and eggs).Probiotics can improve poultry health.The present study was conducted to investigate the impact of a probiotics,Enterococcus faecium NCIMB 11181(E.faecium NCIMB 11181)on the intestinal mucosal immune responses,microbiome and barrier function in the presence or absence of Salmonella Typhimurium(S.Typh-imurium,ST)infection.Methods:Two hundred and forty 1-day-old Salmonella-free male broiler chickens(Arbor Acres AA+)were randomly allocated to four groups with 6 replicate cages of 10 birds each.The four experimental groups were follows:(1)nega-tive control(NC),(2)S.Typhimurium,challenged positive control(PC),(3)the E.faecium NCIMB 11181-treated group(EF),(4)the E.faecium NCIMB 11181-treated and S.Typhimurium-challenged group(PEF).Results:Results indicated that,although continuous feeding E.faecium NCIMB 11181 did not obviously alleviate growth depression caused by S.Typhimurium challenge(P>0.05),E.faecium NCIMB 11181 addition significantly blocked Salmonella intestinal colonization and translocation(P<0.05).Moreover,supplemental E.faecium NCIMB 11181 to the infected chickens remarkably attenuated gut morphological structure damage and intestinal cell apoptosis induced by S.Typhimurium infection,as evidenced by increasing gut villous height and reducing intes-tinal TUNEL-positive cell numbers(P<0.05).Also,E.faecium NCIMB 11181 administration notably promoting the production of anti-Salmonella antibodies in intestinal mucosa and serum of the infected birds(P<0.05).Addition-ally,16S rRNA sequencing analysis revealed that E.faecium NCIMB 11181 supplementation ameliorated S.Typhimu-rium infection-induced gut microbial dysbiosis by enriching Lachnospiracease and Alistipes levels,and suppressing Barnesiella abundance.Predicted function analysis indicated that the functional genes of cecal microbiome involved in C5-branched dibasic acid metabolism;valine,leucine and isoleucine biosynthesis;glycerolipid metabolism and lysine biosynthesis were enriched in the infected chickens given E.faecium NCIMB 11181.While alanine,asparate and glutamate metabolism;MAPK signal pathway-yeast;ubiquine and other terpenoid-quinore biosynthesis,protein processing in endoplasmic reticulum;as well as glutathione metabolism were suppressed by E.faecium NCIMB 11181 addition.Conclusion:Collectively,our data suggested that dietary E.faecium NCIBM 11181 supplementation could ameliorate S.Typhimurium infection-induced gut injury in broiler chickens.Our findings also suggest that E.faecium NCIMB 11181 may serve as an effective non-antibiotic feed additive for improving gut health and controlling Salmonella infection in broiler chickens.

Supplemental N-acyl homoserine lactonase alleviates intestinal disruption and improves gut microbiota in broilers challenged by Salmonella Typhimurium

Background Salmonella Typhimurium challenge causes a huge detriment to chicken production.N-acyl homoserine lactonase(AHLase),a quorum quenching enzyme,potentially inhibits the growth and virulence of Gram-negative bacteria.However,it is unknown whether AHLase can protect chickens against S.Typhimurium challenge.This study aimed to evaluate the effects of AHLase on growth performance and intestinal health in broilers challenged by S.Typhimurium.A total of 240 one-day-old female crossbred broilers(817C)were randomly divided into 5 groups(6 replicates/group):negative control(NC),positive control(PC),and PC group supplemented with 5,10 or 20 U/g AHLase.All birds except those in NC were challenged with S.Typhimurium from 7 to 9 days of age.All parameters related to growth and intestinal health were determined on d 10 and 14.Results The reductions(P<0.05)in body weight(BW)and average daily gain(ADG)in challenged birds were alleviated by AHLase addition especially at 10 U/g.Thus,samples from NC,PC and PC plus 10 U/g AHLase group were selected for further analysis.S.Typhimurium challenge impaired(P<0.05)intestinal morphology,elevated(P<0.05)ileal inflammatory cytokines(IL-1βand IL-8)expression,and increased(P<0.05)serum diamine oxidase(DAO)activity on d 10.However,AHLase addition normalized these changes.Gut microbiota analysis on d 10 showed that AHLase reversed the reductions(P<0.05)in several beneficial bacteria(e.g.Bacilli,Bacillales and Lactobacillales),along with increases(P<0.05)in certain harmful bacteria(e.g.Proteobacteria,Gammaproteobacteria,Enterobacteriaceae and Escherichia/Shigel a)in PC group.Furthermore,AHLase-induced increased beneficial bacteria and decreased harmful bacteria were basically negatively correlated(P<0.05)with the reductions of ileal IL-1βand IL-8 expression and serum DAO activity,but positively correlated(P<0.05)with the increased BW and ADG.Functional prediction revealed that AHLase abolished S.Typhimurium-induced upregulations(P<0.05)of certain pathogenicity-related pathways such as lipopolysaccharide biosynthesis,shigellosis,bacterial invasion of epithelial cells and pathogenic Escherichia coli infection of gut microbiota.Conclusions Supplemental AHLase attenuated S.Typhimurium-induced growth retardation and intestinal disruption in broilers,which could be associated with the observed recovery of gut microbiota dysbiosis.

Cross-protective effect of acid adaptation on ethanol tolerance in Salmonella Enteritidis

Cross protection can undermine the effectiveness of control measures on foodborne pathogens,and therefore brings major implications for food safety.In this work,the capacity of Salmonella Enteritidis to mount ethanol tolerance following acid adaptation was characterized by analysis of cell viability and cell membrane property.It was observed that preadaptation to pH 4.5 significantly(P<0.05)increased the tolerance of log-phase cells to ethanol;in contrast,stationary-phase cells displayed reduced ethanol tolerance after acid adaptation.However,acid adaptation did not cause cell leakage and morphological change in both log-phase and stationary-phase S.Enteritidis.Fatty acid analysis further revealed that the amount of C_(14:0),C_(17:0 cyclo) and C_(19:0 cyclo) fatty acids was increased,while that of C_(16:1ω7c) and C_(18:1ω7c) fatty acids was decreased,respectively,in response to acid adaptation,regardless of bacterial growth phase.Notably,acid adaptation significantly(P<0.05)increased the proportion of C_(16:0) fatty acid in log-phase cells,but this effect did not occur in stationary-phase cells.Moreover,exogenous addition of C_(16:0) fatty acid to stationary-phase acid-adapted cultures was able to enhance bacterial ethanol tolerance.Taken together,C_(16:0) fatty acid is involved in the growth-phase-dependent protective effect of acid adaptation on ethanol tolerance in S.Enteritidis.

Exopolysaccharides of Lactobacillus rhamnosus GG ameliorate Salmonella typhimurium-induced intestinal inflammation via the TLR4/NF-κB/MAPK pathway

Background Salmonella typhimurium(S.T),as an important foodborne bacterial pathogen,can cause diarrhea and gastroenteritis in humans and animals.Numerous studies have confirmed that exopolysaccharides(EPSs)have various biological functions,but the mechanism through which EPSs improve the immunity of animals against the invasion of pathogenic bacteria is unclear.Here,we explored the protective effect of EPSs of Lactobacillus rhamnosus GG(LGG)on the S.T-infected intestine.Methods Mice received adequate food and drinking water for one week before the start of the experiment.After 7 d of prefeeding,2×108 CFU/mL S.T solution and an equivalent volume of saline(control group)were given orally for 1 d.On the fourth day,the mice were treated with 0.5 mg/mL EPSs,1.0 mg/mL EPSs,2.0 mg/mL EPSs,or 2.0 mg/mL penicillin for 7 d.Finally,the body and relative organ weight,histological staining,and the levels of antioxidant enzyme activity and inflammatory cytokines were determined.Results The S.T-infected mice exhibited symptoms of decreased appetite,somnolence,diarrhea and flagging spirit.Treatment with EPSs and penicillin improved the weight loss of the mice,and the high dose of EPSs showed the best therapeutic effect.EPSs significantly ameliorated S.T-induced ileal injury in mice.High-dose EPSs were more effective than penicillin for alleviating ileal oxidative damage induced by S.T.The mRNA levels of inflammatory cytokines in the ileum of mice showed that the regulatory effects of EPSs on inflammatory cytokines were better than those of penicillin.EPSs could inhibit the expression and activation of key proteins of the TLR4/NF-κB/MAPK pathway and thereby suppress the level of S.T-induced ileal inflammation.Conclusions EPSs attenuate S.T-induced immune responses by inhibiting the expression of key proteins in the TLR4/NF-κB/MAPK signaling pathway.Moreover,EPSs could promote bacterial aggregation into clusters,which may be a potential strategy for reducing the bacterial invasion of intestinal epithelial cells.

Intracranial infection and sepsis in infants caused by Salmonella derby:A case report

BACKGROUND Salmonella derby(S.derby)is a Gram-negative diplococcus that is common in the digestive tract.Infected patients generally experience symptoms such as fever and diarrhea.Mild cases are mostly self-healing gastroenteritis,and severe cases can cause fatal typhoid fever.Clinical cases are more common in children.The most common form of S.derby infection is self-healing gastroenteritis,in which,fever lasts for about 2 d and diarrhea for<7 d.S.derby can often cause bacterial conjunctivitis,pneumonia,endocarditis,peritonitis and urethritis.However,intracranial infections in infants caused by S.derby are rare in clinical practice and have not been reported before in China.CASE SUMMARY A 4-mo-old female infant had recurrent fever for 2 wk,with a maximum body temperature of around 39.4°C.Treatment for infectious fever in a local hospital was ineffective,and she was admitted to our hospital.Before admission,there was one sudden convulsion,characterized by unclear consciousness,limb twitching,gaze in both eyes,and slight cyanosis on the face.Cerebrospinal fluid(CSF)culture was positive for Gram-negative bacilli,which conformed to S.derby.After treatment with meropenem and ceftriaxone antibiotics,the patient was discharged home in a clinically stable state after 4 wk of treatment.CONCLUSION We reported a rare case of S.derby cultured in CSF.S.derby enters the CSF through the blood–brain barrier,causing purulent meningitis.If not treated timeously,it can lead to serious,life-threatening infection.